{
  "cases": [
    {
      "expected": {
        "contextWindow": 64000,
        "maxOutput": 8192,
        "source": "user"
      },
      "fn": "merge_limits",
      "input": {
        "layers": [
          {
            "contextWindow": 64000,
            "maxOutput": null,
            "source": "user"
          },
          {
            "contextWindow": 128000,
            "maxOutput": 8192,
            "source": "endpoint"
          },
          {
            "contextWindow": 1000000,
            "maxOutput": 384000,
            "source": "preset"
          }
        ]
      }
    },
    {
      "expected": {
        "contextWindow": 128000,
        "maxOutput": 384000,
        "source": "endpoint"
      },
      "fn": "merge_limits",
      "input": {
        "layers": [
          {
            "contextWindow": 128000,
            "maxOutput": null,
            "source": "endpoint"
          },
          {
            "contextWindow": 1000000,
            "maxOutput": 384000,
            "source": "preset"
          }
        ]
      }
    },
    {
      "expected": {
        "contextWindow": 200000,
        "maxOutput": 4096,
        "source": "user"
      },
      "fn": "merge_limits",
      "input": {
        "layers": [
          {
            "contextWindow": null,
            "maxOutput": 4096,
            "source": "user"
          },
          {
            "contextWindow": 200000,
            "maxOutput": null,
            "source": "preset"
          }
        ]
      }
    },
    {
      "expected": {
        "contextWindow": 1000000,
        "maxOutput": 384000,
        "source": "preset"
      },
      "fn": "merge_limits",
      "input": {
        "layers": [
          {
            "contextWindow": 1000000,
            "maxOutput": 384000,
            "source": "preset"
          }
        ]
      }
    },
    {
      "expected": {
        "contextWindow": null,
        "maxOutput": null,
        "source": "endpoint"
      },
      "fn": "merge_limits",
      "input": {
        "layers": [
          {
            "contextWindow": null,
            "maxOutput": null,
            "source": "user"
          },
          {
            "contextWindow": null,
            "maxOutput": null,
            "source": "endpoint"
          }
        ]
      }
    }
  ],
  "crateVersion": "0.1.2",
  "description": "layers 按优先级从高到低（user > endpoint > preset），从左往右两两合并 merge(merge(l0, l1), l2)。merge(hi, lo)：hi 两个字段都为空时整条换成 lo（连 source 一起，空的用户设置不能冒充来源）；否则逐字段取 hi 的值、为空才用 lo 的，source 保留 hi 的。推论：所有层都为空时，结果是最后一层（两个 null + 最后一层的 source）—— 调用方看两个值都是 null 即视为「未知」，不看 source。",
  "generatedBy": "cargo xtask gen-spec（期望值由 Rust 参考实现算出，请勿手改）",
  "specVersion": 1,
  "title": "限额逐字段取值"
}